Comprehensive population-wide interventions with a mass media campaign component are demonstrated to increase physical activity behavior and thereby reduce the risks of some cancers. A hierarchy of effects model for mass media campaigns (exposure/awareness/knowledge/attention/intention to behavior change) was proposed by McGuire. However, no population-wide physical activity or other campaign data have ever tested or substantiated this model. The model is currently used, in various more recent formats, in planning health related mass media campaigns, and would benefit from specific empirical testing. This research proposal is to conduct a critical re-analysis of five existing physical activity mass media campaign data sets in order to better understand how mass media campaigns influence physical activity behavior. This project will define the mediators that influence physical activity behavior change. The outcome will be a better understanding of the impact of organized media campaigns upon outcome variables. This will increase understanding of the key ways in which community-wide mass media campaigns produce their effects, which will augment the design and development of future comprehensive public health interventions. The analytic methods will test the relationship of these data with incremental model building. More complex path models will then be developed, using structural equation modeling and assessing best-fit models of the data in terms of hypothesized causal linkages. Mediators will be examined cross-nationally to assess whether the pathways of influence from mass media message awareness to health behavior are similar or different in different populations. Moderator analyses, the examination of campaign effects within sub-groups, will be sought; the pathways will be tested for males and females, by age group, educational attainment, and by obesity status. Ultimately, a more accurate model will be developed from these replicate analyses across data sets, to define and guide the design of future mass media-based population-wide physical activity interventions to reduce cancer risk. Identifying the key ingredients and outcomes of comprehensive media-based physical activity campaigns will enable the research team and others to fine-tune campaign development and planning. These outcomes will promote better use of cancer prevention funding.